It is the central tenant of Core B and this program project that the most appropriate method to study[unreadable] MH is in murine models that expresses frequently seen human MH mutations. Mouse models can provide[unreadable] sufficient tissues for molecular, biochemical, cellular, and physiological analyses by a multidiscipiinary team[unreadable] whose collective goal is to understand the etiology of these myopathies. The use of mice also permits these[unreadable] analyses to be performed in diverse genetic backgrounds.[unreadable] Core B will perform the repetitive tasks that are necessary to support all four Projects. This core will[unreadable] provide an important and integrated facility to receive gene-targeting constructs from Project 1 and Project 3.[unreadable] They will transfect these constructs into ES cells and after the projects identify homologously targeted clones,[unreadable] amplify these clones for blastocyst injection and inject these targeted ES cells into blastocysts to produce[unreadable] chimeras. After confirmation of germline transmission by Projects 1 and 3, Core B will produce MH "knock-in"[unreadable] mice to be studied by all four Projects.[unreadable] Core B will take cDNA constructs from Projects 1, 3 and 4 and package them into HSV1 (RyRs) or[unreadable] Lentivirus (DHPRs) virions to be used for expression of mutated proteins and intracellular reporters in[unreadable] myotube cultures and distribute them as needed to all 4 projects. Core B will make myoblast cell lines from all[unreadable] heterozygous and homozygous MH "knock-in" mice and maintain dyspedic, dysgenic and dyspedic/dysgenic[unreadable] cell lines to be used by all 4 projects.[unreadable] Core B will receive human MHS muscle samples from Core C and maintain myoblast cell lines from[unreadable] these samples to be used by projects 1 and 4.[unreadable] In addition to maintaining MH "knock-in" animal lines Core B will take responsibility for interbreeding[unreadable] these animals with C57BL6 and BalbC mice to produce MH animals with different genetic backgrounds[unreadable] The uniform and consistent supply of exactly the same study models to all four Projects by this[unreadable] Core will allow a truly integrated approach to the study of Malignant Hyperthermia.